/Engine/Source/Runtime/ApplicationCore/Public/GenericPlatform/GenericApplicationMessageHandler.h
The Window Zone is the window area we are currently over to send back to the operating system for operating system compliance.
namespace EWindowZone { enum Type { NotInWindow = 0, TopLeftBorder = 1, TopBorder = 2, TopRightBorder = 3, LeftBorder = 4, ClientArea = 5, RightBorder = 6, BottomLeftBorder = 7, BottomBorder = 8, BottomRightBorder = 9, TitleBar = 10, MinimizeButton = 11, MaximizeButton = 12, CloseButton = 13, SysMenu = 14, Unspecified = 0, } }